On Sun, 25 Mar 2007 21:57:05 -0700, Bennett Price
<bjpriceNOSPAM@itsa.ucsf.edu> wrote:

>
>
>Gerard Bok wrote:
>> On Sun, 25 Mar 2007 06:10:37 GMT, Bennett Price
>> <bjpriceNOSPAM@itsa.ucsf.edu> wrote:
>>
>>>> You plan on using "UNshielded CAT 5 cable" as a 25 foot USB 2 cable? Well,
>>>> I think you'll greatly enjoy the data corruption from the noise interference
>>>> your cable will be subject to. Why bother with Standards anyway...
>>>>
>>> That's why I'm asking. As for Standards, reread what I said about
>>> parallel printer and RS-232 serial cables.
>>
>> Your printer and RS standards operate in the 0.1 Mbps range.
>> Do you realy expect the same leniency at 400 Mbps ?
>> Or are you willing to wait 6 years for your backup to be complete
>> ?
>>
>But I'm not trying to extend USB 2 cables to 4 or 5 times their spec'd
>maximum of 5 meters - 16.5 feet. I need only go about 20-25 feet, less
>than twice the spec'd max.
>
>And of course I'm asking because I don't know if it will work. Everyone
>points to the spec but so far no one has actually reported trying going
>over 5 meters.


Well... a 5-10 foot USB extension cable costs about $4, why
don't you just try it and tell US if it's working ok? I
suggest you buy the largest (lowest) gauge of cable
possible, that you can find I mean, which will tend to raise
the price some as those tend to cost closer to $15 than to
$4... IIRC, Belkin is one manufacturer that lists the gauges
of various offerings, I vaguely recall that mentioned on
listings at Newegg.com but I don't recall for certain if it
was on extension, A/B or what USB cable configuration it
was... this is just an idea of one place and manufacturer
that may have some applicable information.

If you get the extension cable and it doesn't work, buy the
repeater cable. Buy them both and benchmark both ways.
Maybe 20' would work but 25' wouldn't without the repeater.
The whole purpose of the spec is to spec a configuration
that "should" work. You want someone to say they had it
work as if that would be an assurance that if you did it, it
would work... which is not necessary true. If the USB
developers could get > 5 meters to consistently work, they
would've just spec'd it for > 5 meters. Instead, we can see
that with marginal cables, sometimes even 5 meters won't
work.